The optical mouse has been popular for controlling functions of computers and other electronic devices. The conventional optical mouse is too big and unsuitable for use in many portable electronic devices, however, such as personal digital assistants, telephones, and the like. Accordingly, other types of conventional input devices such as TOUCHPAD™ and THINPAD™ devices, and LOGITECH™ REVOLUTION™ mice, have been developed for use in portable electronic devices such as laptop computers, phones and the like. These input devices have become more important as portable electronic devices continue to incorporate additional functionality, such as electronic mail, wireless computing, photography and so on.
Conventional puck-based input devices are attractive for handheld electronic devices because of their low profile. In some conventional puck-based input devices, a resilient mechanism, such as a spring, is deployed in association with the puck to maintain a desired position of the puck. The resilient mechanism is arranged to bias the puck to return to a center position after the puck has been moved to an off-center position, in which the user captures a user input. Unfortunately, such mechanisms are subject to mechanical wear and tear over time, and susceptible to the ingress of debris and moisture potentially resulting in device failure. In rate control devices such as the IBM™ TRACKPOINT™ the position of the stick maps to the velocity of the cursor. For rate control devices, accurate re-centering is important because if the puck is not returned precisely to center, the cursor may drift when the user is not touching it. To work around this problem, these conventional input devices typically employ a sufficiently large central “dead zone,” or use a very stiff restoring spring, both of which are detrimental to a good user experience. The NEUROPOINTER™ by NEC™ is an example of a conventional portable puck-based navigation device which uses a rubber membrane to re-center the puck. Because the membrane is essentially a linear spring, the re-centering accuracy is relatively poor.
Other conventional input devices attempt to address the accuracy of re-centering a puck with re-centering mechanisms having alternative force restoring force profiles. Unfortunately, these conventional input devices are too thick to fit in many portable electronic devices.
Users continue to demand more precision and accuracy in user input devices of portable electronic devices, while designers face continual pressure toward increasing miniaturization and increased functionality. Faced with these challenges, conventional input devices often fall short of market expectations by exhibiting inaccurate puck centering and positioning.
Further details concerning various aspects of prior art devices and methods are set forth in: (1) U.S. patent application Ser. No. 11/606,556 entitled “Linear Positioning Input Device” to Harley filed Nov. 30, 2006; (2) U.S. Provisional Patent Application Ser. No. 60/794,723 entitled “Linear Positioning Device” to Harley filed Apr. 25, 2006; (3) U.S. patent application Ser. No. 10/723,957 entitled “Compact Pointing Device” to Harley filed Nov. 24, 2003; (4) U.S. patent application Ser. No. 11/407,274 entitled Re-Centering Mechanism for an Input Device” to Orsley filed Apr. 19, 2006; (5) U.S. patent application Ser. No. 11/923,653 entitled “Control and Data Entry Apparatus” to Orsley filed Oct. 25, 2007, each of which is hereby incorporated by reference herein, each in its respective entirety.
What is need is a capacitive sensing input device that is capable of re-centering itself accurately and quickly, may be re-centered from both slide and tilt positions, has a small form factor, is more mechanically robust and less susceptible to the effects of wear and tear, may be fabricated as a sealed package that prevents the ingress of dirt and moisture, may be employed as a replacement mechanism for conventional 5-way navigation devices as well as mouse tilt-wheel mechanisms, and may be manufactured without undue cost or complexity.